Public involvement has become important in public project planning so it is necessary to consider local residents as players in the planning. However, if there are many local residents, it is difficult to divide them into player groups. In this study, the process of setting players among the local residents is proposed. This process is applied to the Yoshino River dam construction problem, and how this process can help in analyzing conflict is discussed. Furthermore, numerous small municipalities are recently being clustered and recomposed into larger municipalities in Japan. This decomposition influences not only the Yoshino River weir conflict but will also affect other public project plans in the future. With this in mind, the possibility of managing the Yoshino River conflict in the future is analyzed. JEL Classification: C62, C65, C72